Spring-loaded geared flap structure

ABSTRACT

A spring-loaded flap rudder or flap stabilizer adapted to be mounted to the hull structure of a ship. In a geared version of the invention, the rudder or stabilizer includes a member and a gear including teeth. The rudder or stabilizer also includes a flap member pivotally connected to the member with a component, such as a spring, arranged to limit jamming between the gear and a movable flap gear. The flap gear includes a rod movably engaged in a socket of the flap member and gear teeth for engagement with the teeth of the gear.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to marine craft. More particularly, thepresent invention relates to the rudders and stabilizers of marinecraft. Still more particularly, the present invention relates to flaprudders and anti-roll stabilizers.

2. Description of the Prior Art

A rudder in the form of a pivotable plate or a displacement body isdisposed at the stem of a ship. When the rudder is actuated, it ispivoted by a controlled angle of deflection. That movement develops ahydrodynamic transverse force which acts on the rudder andcorrespondingly on the stem of the ship. This force produces the turningtorque required to steer the ship. This hydrodynamic transverse forceproduces a torque on the rudder with respect to the rudder stock whichis to be supplied by the steering gear.

There are single member rudders, flap rudders and geared flap rudders.The current basic arrangement for a geared flap rudder includes a ruddermember with an associated fixed gear that engages with a flap memberhaving an associated movable gear. The rudder member is oriented forwardof the flap member when viewing the vessel bow to stern. The forwardgear of the rudder member is joined to the hull and the aft gear of theflap member is joined to the flap member. As the rudder stock is turned,the flap angle is double the rudder angle. There are no sliding parts,no energy absorber and no bearings other than on the flap member to therudder member. In another design, the rudder member includes apositively controlled fin that is deflected in opposition to the mainrudder deflection without the aid of powered steering gear in order toestablish torque equilibrium with respect to the rudder stock.

A limitation of the existing geared flap rudder design is experiencedwhen the rudder member or the flap member is bent, such as may occurwhen either contacts large debris. If the bend is significant enough, itis not possible to move either or both of the rudder member and the flapmember as desired to change their respective positions. Thatcircumstance will compromise ship maneuverability. Another limitation ofthe existing geared flap rudder design occurs when debris, such as a logfor example, wedges into the gearing, rendering it difficult orimpossible to change the position of the gear. That too, will compromisethe ability to maneuver the ship.

What is needed is a geared flap rudder that is configured to minimizethe operation of the rudder when either or both of the rudder and theflap are impacted and bent. What is also needed is a geared flap rudderthat is configured to avoid gear lockup resulting from debris gettinginto the gears that exist on the flap and the rudder. The geared flaprudder should remain functional for normal operations whether or not theflap, the rudder or the gears are compromised.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a spring-loaded flaprudder that is configured to minimize the operation of the rudder wheneither or both of the rudder and the flap are impacted and bent. It isalso an object of the present invention to provide a spring-loadedgeared flap rudder that is configured to avoid gear lockup resultingfrom debris getting into the gears that exist on the flap and therudder. The geared flap rudder of the present invention remainsfunctional for normal operations whether or not the flap, the rudder orthe gears are compromised.

These and other objects are achieved with the present invention, whichis a spring-loaded geared flap rudder. There is no other flap rudderavailable that is spring-loaded. The spring-loaded geared flap rudder ofthe present invention is substantially advantageous over any existingflap rudder. The spring is adjustable and so can be used to account forany misalignment of components of the flap rudder, including the gearsof a geared flap rudder. That makes the present invention less costly toproduce in addition to being less prone to jamming and deflections.Existing rudders must be manufactured and put together with tightertolerances than is necessary with a spring-loaded flap rudder so thatany problems of misalignment can be minimized.

The rudder joins the aft gear to a rod which fits into a cylinder andthat cylinder is joined to the flap. At the aft end of the cylinderthere is a spring. If the rudder stock is bent forward or aft, thespring deflects in or out to prevent jamming. If the rudder stock isbent to the side, the rod rotates in the cylinder and prevents jamming.This interface joins the flap and the moving gear together. Thethickness of the gears can be made sufficient so that any relativelysmall branch, for example, that gets in the gear will be pulverized bythe gear movement and any larger log will not fit between the gearteeth. The interface includes a cover plate that protects against itemsentering the gearing from above. The effective arm of the flap isconstant, so that there is just as much force keeping the flap extendedat 45 degrees as there is keeping it from wobbling at 0 degrees.

The invention is a spring-loaded rudder adapted to be mounted to thehull structure of a ship, the rudder comprising a rudder memberincluding a rudder stock rotatably connectable to the hull structure, arudder gear connectable to the hull structure, the rudder gear includingrudder teeth, a flap member pivotally connected to the rudder member,wherein the flap member includes a socket and a flap gear including arod movably engaged in the socket of the flap member and gear teeth forengagement with the rudder teeth of the rudder gear. The rudder includesa gear cover connectable to the hull structure and the rudder gear tocover the rudder teeth and the gear teeth. The rod of the flap gear isarranged for rotational and axial movement. The flap gear includes aspring positioned in the socket and arranged to enable axial movement ofthe rod of the flap gear. The flap member is pivotally connected to atrailing edge of the rudder member. The invention is, more generally, aspring-loaded flap rudder, whether or not the flap and rudder membersinclude gears. Further, the invention is still more generally a deviceto enable controlled movement of a marine craft with a control planethat may be a rudder, which is oriented perpendicular to the waterlineof the marine craft, or that may be an anti-roll stabilizer such as thatused to minimize vessel roll in rough seas, which stabilizers areoriented parallel the waterline of the marine craft.

The introduction of the spring element within the cylinder at the flapgear to rudder gear interface ensures that the rudder remainsoperational when either is bent and when debris wedges into the gearing.This makes operation of the ship more certain and safer than is the casewhen existing geared flap rudders are used. This configuration may alsobe employed on anti-roll stabilizer components. These and other featuresand advantages of the present invention will be understood upon reviewof the following detailed description, the accompanying drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the spring-loaded geared flap rudder of thepresent invention.

FIG. 2 is a top view of the rudder of the present invention with therudder and flap aligned.

FIG. 3 is a top view of the rudder of the present invention with therudder and flap angled with respect to a centerline.

FIG. 4 is a top cross-sectional view of the rudder of the presentinvention.

FIG. 5 is a top view of the flap member of the rudder of the presentinvention.

FIG. 6 is an end view of the flap member.

FIG. 7 is a top view of the flap gear showing the rod portion thatinserts into the socket of the flap member.

FIG. 8 is an end view of the rod.

FIG. 9 is an end view of the rudder of the present invention shown bentwhile also showing that it is not jammed with respect to the flap.

DETAILED DESCRIPTION OF THE INVENTION

A spring-loaded geared flap rudder 10 of the present invention is shownin FIGS. 1-4. The flap rudder 10 includes a rudder member 12, a flapmember 14, a rudder gear 16, a flap gear 18 and a gear cover 20. Theflap rudder 10 is connected to a hull structure 22 of a ship aft of apropeller. Specifically, a rudder stock 24 of the rudder member 12passes through a rudder port 26 of the hull structure 22 into aninterior portion of the ship and joined to couplings and gearingcontrolled to cause movement of the rudder member 12. The rudder member12 to hull 22 interface is sealed, such as with a split-ring seal 28,for example.

The rudder member 12 is rotatably mounted on the hull structure 20 bythe rudder stock 24 such that the rudder member 12 is suspended from thehull structure 22. The flap member 14 is pivotally mounted on a trailingedge 30 of the rudder member 12 by way of a pivot rod 32.

The rudder gear 16 is connected to the hull structure 22, such as bywelding it in place. The rudder gear 16 remains fixed in position wheneither or both of the rudder member 12 and the flap member 14 move. Theflap gear 18 is connected to the flap member 14 and is arranged to movewith movement of either or both of the rudder member 12 and the flapmember 14. As shown in FIGS. 5-8, the flap member 14 and the flap gear18 are separate components of the rudder 10. The flap member 14 includesa socket 34 and a retaining bushing 36 at its leading edge. The flapmember 14 further includes a component that permits axial movement ofthe flap gear 18 with respect to the socket 34. For example, that membermay be a spring 38. The flap gear 18 includes a gear section 40 and arod section 42. The socket 34, the bushing 36 and the rod section 42 areconfigured so that the rod section 42 fits into the socket 34 and isremovably retained therein by the bushing 36. When seated in position inthe socket 34, the rod 42 is adjacent to and in contact with a wearplate 44 spaced between the rod 42 and the spring 38.

The rudder member 12 and the flap member 14 are joined together throughthe pivot rod 32, the location of which establishes the spacing betweenthose members. The flap member 14 moves with respect to the ruddermember 12 by actuation of the pivot rod 32 and that movement isregulated by engagement of teeth 46 of the flap gear 18 with teeth 48 ofthe rudder gear 16. While the rudder gear 16 remains in a fixedposition, the flap gear 18 moves with movement of the flap member 14, ascan be seen in a comparison of the location of the teeth 46 with respectto the location of the teeth 48 shown in FIGS. 2 and 3.

The flap member 14 and the flap gear 18 combination permits continuedfunctioning of the rudder 10 under conditions when either or both of therudder member 12 and the flap member 14 are bent, torqued, twisted orotherwise less than completely aligned. That continued functioning isenabled because the rod 42 can rotate within the socket 34 so that theteeth 46 of the flap gear 18 will remain aligned with the teeth of therudder gear 16 when the rudder member 12 and the flap member 14 aremisaligned. In addition, the flap member 14 and the flap gear 18combination permits continued functioning of the rudder 10 underconditions when debris gets into the gears. That continued functioningis enabled in that situation because the spring 38 will take up axialdisplacement of the flap gear 18 within the socket 34 until the debrisis either crushed or passes out of the space between teeth 46 and teeth48. The rotational, compressive and elongate characteristics of the flapgear 18 maintain rudder 10 operation whether the rudder stock 24 bentsideways, fore or aft. The spring 38 has a spring value sufficient tokeep the flap gear 18 in place when the rudder member 12 and the flapmember 14 are properly aligned but will compress when needed. Thecompression in the spring 38 can be adjusted after the rudder 10 is inplace to a value sufficient for the rudder 10 to operate as intended.Further, the inclusion of the spring 38 provides adjustability tocorrect misalignment of components of the rudder 10 including the rudderstock 24, the fixed rudder gear 16 and the movable flap gear 18. This isan advantage over existing flap rudders which must be built torelatively tighter tolerances to reduce the possibility of misalignmentthat may result in rudder limitations including failure.

The gear cover 20 is connected to the rudder gear 16 and to the hullstructure 22. It is located over the interface between the teeth 46 ofthe flap gear 18 and the teeth 48 of the rudder gear 16. It is providedto minimize damage to the rudder 10 at that interface resulting fromcontact with debris or impact with a structure. As illustrated in FIG.9, the rudder 10 remains operational with no jamming of the rudder gear16 and the flap gear 18 even with a bent rudder member 12 that is shownin the figure as an example with the rudder member 12 about 15° out ofalignment. Prior flap rudders would be incapacitated with such a bend ofthe rudder member.

The components of the rudder 10 of the present invention may befabricated of one or more materials suitable for their intendedfunctions in the environment of expected operation. For example, therudder member 12, the flap member 14, the rudder gear 16 and the flapgear 18 may be fabricated of a metal such as steel, including stainlesssteel. The bushing 36 of the flap member 18 may be fabricated ofmetallic or nonmetallic material. For example, the bushing 36 may be abushing available from Thordon Bearings, Inc., of Burlington, Ontario,Canada.

The rudder is adapted to be mounted to the hull structure of a ship andincludes a rudder member including a rudder stock rotatably connectableto the hull structure of the ship, a rudder gear connectable to the hullstructure, the rudder gear including rudder teeth, a flap memberpivotally connected to the rudder member, wherein the flap memberincludes a socket and a component in the socket and a flap gearincluding a rod movably engaged and rotatable in the socket of the flapmember and gear teeth for engagement with the rudder teeth of the ruddergear, wherein the component permits axial movement of the rod in thesocket to adjust alignment of the rudder gear and the flap gear andprevent jamming thereof In an embodiment, the rudder is movablyaffixable to a ship having a hull structure. The rudder includes arudder member joined to a flap member, wherein the flap member includesa socket, a component in the socket and a rod rotatable in the socketand engaged with the component for axial movement within the socket,wherein the rod and the component space the flap member from the ruddermember. The component may be a spring, a hydraulic device or a similarsort of control component.

The geared flap rudder described herein may be similarly implementedwith a rotatable control surface such as an anti-roll stabilizerdesigned to minimize marine craft roll. For example, a modifiedanti-roll stabilizer may include a stabilizer adapted to be mounted tothe hull structure of a ship. It includes a member including a stockrotatably connectable to the hull structure of the ship, a stabilizergear connectable to the hull structure, the stabilizer gear includingteeth, a flap member pivotally connected to the member, wherein the flapmember includes a socket and a component in the socket, and a flap gearincluding a rod movably engaged and rotatable in the socket of the flapmember and gear teeth for engagement with the teeth of the stabilizergear, wherein the component permits axial movement of the rod in thesocket to adjust alignment of the stabilizer gear and the flap gear andprevent jamming thereof. The component may be a spring, a hydraulicelement or other suitable device.

It is to be understood that various modifications may be made to theinvention described herein without departing from the spirit and scopeof the invention. Accordingly, other embodiments are within the scope ofthe claims appended hereto.

What is claimed is:
 1. A rudder adapted to be mounted to the hullstructure of a ship, the rudder comprising: a. a rudder member includinga rudder stock rotatably connectable to a hull structure of a ship; b. arudder gear connectable to the hull structure, the rudder gear includingrudder teeth; c. a flap member pivotally connected to the rudder member,wherein the flap member includes a socket and a spring in the socket;and d. a flap gear including: i. a rod movably engaged and rotatable inthe socket of the flap member; and ii. gear teeth for engagement withthe rudder teeth of the rudder gear.
 2. A stabilizer adapted to bemounted to the hull structure of a ship, the stabilizer comprising: a. amember including a stock rotatably connectable to a hull structure of aship; b. a stabilizer gear connectable to the hull structure, thestabilizer gear including teeth; c. a flap member pivotally connected tothe member, wherein the flap member includes a socket and a component inthe socket; and d. a flap gear including: i. a rod movably engaged androtatable in the socket of the flap member; and ii. gear teeth forengagement with the teeth of the stabilizer gear, wherein the componentpermits axial movement of the rod in the socket to adjust alignment ofthe stabilizer gear and the flap gear and prevent jamming thereof. 3.The stabilizer of claim 2 wherein the component is a spring.